Coarse aggregate depressing machine for concrete



March 21, 1961 s. A. HUMPHREY 2,975,684

COARSE AGGREGATE DEPRESSING MACHINE FOR CONCRETE Filed April 16, 1958 2 Sheets-Sheet 1 20 INVENTOR.

jg /vwr fluMP/mr March 21, 1961 s. A. HUMPHREY 2, 75,684

COARSE AGGREGATE DEPRESSING MACHINE FOR CONCRETE Filed April 16, 1958 2 Sheets-Sheet 2 firm/win") United States Patent COARSE AGGREGATE DEPRESSING MACHINE FOR CONCRETE a This invention relates toa machine for depressing the coarse aggregate in a concrete mass in order to facilitate proper finishing and producing a long wearing durable surface. i .It has been a long existing problem to provide a concrete surface which can be easily and readily finished wherein the coarse aggregate has been depressed and the mortar paste produced on the top of the concrete without excessive moisture to thereby permit a smooth, long wearing, durable surface to be produced on the coricrete mass without requiring excessive vibration or float.- ing operations to be performed. f

It is an object of my present invention to provide a device for depressing the coarse aggregate a predetermined selected distance below the finished surface of the concrete even with a relatively heavy low water content mass, thus greatly increasing the durability of the finished surface and preventing excessive moisture from accumulating in theupper marginal thickness of the mass. Y

It is another object to provide a device particularly designed to produce a flat, uniformly contoured surface wherein the coarse aggregate has been depressed mechan ically a predetermined distance below the top surface thereof. a It is .still a further object to provide a device for depressing the coarse aggregate into a concrete mass a uniform predetermined distance while producing a uniform plane surface which can be easily and quickly finished in the usual manner thus eliminating much of the time normally required for vibration'of the mass while still producing an easily finished dense surface layer containing only'a minimum proportion of water.

More specifically it is an object to provide a combined coarse aggregate depressing device and a smoothing bar following the same and attached thereto to prepare the surface for finished trowling without additional work thereon. a ;It is still' a further object to provide a devicewhich iseither h'and operated or power driven for the purpose set-forth above.-- a a 1 It is still another object to provide a device of the class described which is particularly constructed to facilitate cleaning thereof and which is specifically constructed to prevent accumulation of aggregate particles therewithin.

These and other objects and advantages of my invention will more fully appear from the following descriptions made in connection with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views, in

which;

Fig.'1 is a perspective view of a device embodying my invention;

Fig. 2 is a side elevational view thereof;

Fig. 3 is a vertical sectional view taken substantially along the line 3--3 of Fig. 2;

Fig. 4 is a perspective view of an alternative form of my invention; and,

2 ,975,684 Patented Mar. 21, 196).

Fig. 5 is a perspective view of stillanother form of this invention.

In the form shown in Figs. 1 and 2, I provide a central supporting shaft 7 journaled in suitable bearings provided in a pair of end supporting structures 8 such as the plate members illustrated. A yoke having a pair of arms 9 and a cross bar 10 is connected with the supporting structure as by having the lower ends of the arms 9 journaled on the outer end portions of the shaft 7. A draw bar 11 connected in fixed relation to the cross bar 10 permits the unit to be moved back and forth across the concrete surface as best shown in Fig. 1. A pair of sprocket wheels 12 are respectively journaled at the end portions of the mounting plates 8 and a pair of endless conveyor chains 13 are respectively trained around said sprocket wheels 12. A center supporting sprocket 14 has its lower periphery lying in the plane defined by the lower peripheries between two end sprockets 12 and the teeth thereof are engaged in intermediate portions of the opposed upper and lower runs of the endless conveyor chain 13 as best shown in Fig. 2.

In the form shown, a pair of shafts 15 extend between the end sprockets 12, and a pair of intermediatory disposed sprockets 16 are respectively carried thereby and are respectively transversely aligned between laterally opposed front end sprockets 12 and a laterally opposed rear end sprocket 12. A central supporting sprocket 17 is mounted on an intermediate portion of the main supporting shaft 7 and supports the intermediate portion of center shaft 18 as illustrated. All of the sprocket wheels are designed to provide supporting guides for the endless conveyor chains '13 and 18 and position the lower runs of said chains in a plane closely spaced above the surface of the concrete mass on which the device is being operated.

In the form illustrated, each of the chains 13 has a plurality of spacer bars or struts 19 respectively fixed to the links thereof and a plurality of rods 20 are respectively connected in fixed relation to said spacer bars 19 as best shown in Fig. 2, and extend across the full width of the machine as shown in Fig. 1.- The spacing between the bars 20 is such that the coarse aggregate sought to be depresssed is engaged by said bars but the finer particles in the mass are permitted to pass through the spaces therebetween so that only the relatively fine aggregate of the concrete will belpresent in the upper finishing layer thereof. The amount of depression of the coarse aggregate will depend upon the consistency of the concrete, the weight of the device and the surface area on which the rods are supported and this can be selectively engaged to produce any desired amount of depression of the coarse aggregate particles.

As best shown in Fig. 2, the lower run of the rods 20 lie in a uniformplane and are uniformly spaced apart across the entire lower run. It will be apparent, however, that as the rods proceed around the sprockets 12 at the ends of the run, the spacing therebetween will be substantially greater than that along the top and bottom runs. Thus it will be apparent that any aggregate material which is forced upwardly through the spaces between rods will be permitted to drop out at the ends of the run as the rods pass around the sprocket wheels and the spacing therebetween is thus increased. This prevents accumulation of aggregate within the device and greatly facilitates maintaining and cleaning thereof.

The provision of the endless conveyor chains on which the rods are mounted permits a relatively large area to be engaged by the rods and thus provides for greater support for the device and thus permitting use of a substantially heavier weight which will be exerted on each individual rod as it initially engages the aggregate particles during its travel around the leading sprocket wheels 12 so that each aggregate particle will be depressed substantially the same amount and a uniform flat surface will be produced by the device. 7

Fig. 4 illustrates a modified form of the invention which includes the structure previously described with a surfacmg member mounted in connection with the arms 9 of the yoke so that said surfacing member can be engaged with the concrete surface substantially adjacent the trailing end of the endless conveyor chains 13 and 18. Thus, when the device is drawn back over the surface, the cross bar 21 will be engaged with said surface to smooth and seal the same preparatory to trowling or finishing.

The Wheels 23 are journaled on shafts 25 which are fixed to plates 26. The plates 26 are vertically adjustable on mounting plates 27 which are fixed to the end plates 8 of the supporting frame structure.

In Fig. 5, another modified form of the invention is illustrated wherein the entire unit is power driven being a suitable source of motive power such as the gasoline engine 22 which applies power to the conveyor chains 13 and 18 as by being connected to the drive shaft 15 as illustrated. The actual construction of the rod and chain assembly is identical to that illustrated in Figs. 1 and 2 previously described herein, but instead of the yoke and handle arrangement for manual operation, the device is driven by the gas engine 22. The weight of the unit is supported on wheels 23 which are transversely spaced apart a distance equal to the spacing between the concrete forms 24 and serve to support the lower run of the bars at the desired elevation.

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the parts without departing from the scope of my invention which generally stated consists in the matter set forth in the appended claims.

What I claim is:

1. A device for depressing the coarse aggregate a predetermined distance below the surface of a plastic concrete mass, said device comprising a supporting frame, guiding sprocket wheels journaled for rotation on said frame with the lower peripheries of said wheels all lying on the same plane, an endless chain conveyor structure trained about said wheels for movement therearound and supported thereon, a plurality of transversely disposed parallel rods carried by said endless conveyor structure and being mounted in spaced relationship outwardly therefrom, each of said rods being spaced apart one from another at such a distance to engage and depress the coarse aggregate in a concrete mass into a plane disposed a predetermined distance below the surface layer of the mass and permitting a finer aggregate to pass upwardly through the spaces between said rods, and means for moving the unit across the surface of a concrete mass to cause the endless conveyor rod and chain assembly to travel around the supporting end guiding wheels journaled on said frame while progressively engaging the rods with the coarse aggregate particles of the concrete.

2. The structure set forth in claim 1 and intermediately disposed sprocket wheels having their lower peripheries in the same plane with the lower peripheries of the guiding sprocket wheels and journalled on said supporting frame and meshed with the respective chains of the conveyor structure to provide intermediate support therefor and maintain the lower runs of the chains generally in a continuous plane.

3. The structure set forth in claim 1 and a plurality of weight supporting wheels mounted on said frame in laterally spaced relation thereto for engagement with the forms of said concrete for supporting said device thereon and positioning the lower run of the rod and conveyor assembly at a predetermined elevational distance.

4. The structure set forth in claim 1 and a power source carried by said frame for causing movement of the device over the surface of a concrete mass.

5. The structure set forth in claim 4 and said power source being connected with at least one of the guiding sprocket wheels.

6. A coarse aggregate depressing device for concrete comprising supporting means, conveyor guiding means mounted on said supporting means, an elongated endless flexible conveyor structure mounted on said guiding means and trained thereabout for movement therearound and defining an upper and a lower run, a plurality of parallel spaced apart transversely disposed depressing rods carried by said conveyor structure and being mounted in spaced relationship outwardly therefrom, the rods carried by the lower run of said conveyor structure defining a plane adapted to depress coarse aggregate to a predetermined distance below the surface of the concrete.

7. The structure set forth in claim 6 and a smoothing bar carried by said supporting means and being arranged to follow said depressing device for engagement with the surface of the concrete over which the rods have passed.

8. The structure set forth in claim 6 and a hand operated yoke member plvotally mounted with respect to said supporting means and being arranged for pivotal rotation along a plane substantially normal to said lower run, a smoothing bar carried by said yoke whereby the elevation thereof can be controllably varied by the arcuate swinging of said yoke to selectively engage said bar with the surface of the concrete substantially adjacent the trailing end of the conveyor and rod assembly.

References Cited in the file of this patent UNITED STATES PATENTS 1,312,518 Clark Aug. 12, 1919 1,344,916 McArdle June 29, 1920 1,623,142 Wal h Apr. 5, 1927 2,152,264 Loft Mar. 28, 1939 

